INSECTS 



279 



tant organs. They are used for feeling and for smelling, 

 and, in some insects, for hearing (see Fig. 104). 



On the lower side of the head we find the peculiar mouth. 

 Insects do not have lips, tongue, and teeth in the ordinary 

 sense. They have what are called mouth parts, and these 

 six mouth parts are variously arranged in different insects. 

 In a grasshopper they are arranged for biting. In a bug 

 they are arranged for piercing 

 and slicking. In a fly they are 

 arranged for lapping (see Fig. 



One of the most surprising 

 things about an insect is that it 

 breathes with its abdomen. That is 

 to say, along the side of the ab- 

 domen are found little openings 

 called spiracles. These open into 

 tubes called trachea, which branch 

 and run to all parts of the body, 

 even out into the wings. 



Now think of the activity of 

 an insect as compared with your 

 own. How many times the length 

 of its own body can a grasshopper jump? How many 

 times can you? It is perfectly evident that insects far 

 excel us in muscular activity in proportion to their size. 

 A man would have no trouble jumping over the Wool- 

 worth Building if he could jump like a flea. The breath- 

 ing-plan of insects has a good deal to do with their activity. 

 It permits oxygen to get very quickly to all parts of the 

 body. In other words, insects do not get "out of breath" 

 the way we do. 



FIG. 105. Drawing to show the 

 complicated mouth parts of 

 an insect. 



